{
  "slug": "smoking-lung-carcinoma",
  "title": "Cigarette Smoking as a Major Cause of Lung Carcinoma",
  "claim": "Sustained cigarette smoking causally initiates a substantial (major) share of human lung carcinomas, as shown by exposure-response across independent populations, incidence decline after cessation, and a carcinogen mechanism that leaves a dose-scaled molecular fingerprint in the tumours.",
  "update_date": "2026-10-05",
  "search_cutoff": "2026-10-05",
  "framework_for_addendum": "HSEF v5.3 causal distinctions",
  "historical_scorecard_schema": "5.4",
  "regraded": false,
  "status": "curated_local_addendum",
  "full_academic_review_complete": false,
  "summary": "Epidemiology, cessation, experimental carcinogenesis and tumour signatures converge on smoking as a major causal route. Remaining research questions concern individual susceptibility, persistent injury and attribution among overlapping exposures, rather than whether the overall causal relationship exists.",
  "timeline": [
    {
      "year": "1950",
      "source_id": "P14772469",
      "design": "Historical hospital case-control report",
      "finding": "A foundational report examined smoking and lung carcinoma.",
      "limit": "Metadata-only anchor in this update; its original numerical results were not re-examined.",
      "historical_anchor_only": true
    },
    {
      "year": "1950",
      "source_id": "P15415260",
      "design": "Independent historical case-control report",
      "finding": "A separate report examined smoking in confirmed lung-carcinoma cases.",
      "limit": "Metadata-only anchor; hospital selection and recall remain design limits.",
      "historical_anchor_only": true
    },
    {
      "year": "1996",
      "source_id": "P8832894",
      "design": "Carcinogen-adduct mapping",
      "finding": "Benzo[a]pyrene-related adducts targeted major lung-cancer TP53 mutation hotspots.",
      "limit": "An adduct mechanism does not identify the initiating cause of each individual tumour.",
      "historical_anchor_only": false
    },
    {
      "year": "2000",
      "source_id": "P10926586",
      "design": "National trends plus case-control synthesis",
      "finding": "Stopping smoking greatly reduced subsequent lung-cancer risk.",
      "limit": "Nonrandomized cessation and historical exposure reconstruction require consideration.",
      "historical_anchor_only": false
    },
    {
      "year": "2004",
      "source_id": "P15213107",
      "design": "British Doctors long-term cohort",
      "finding": "Long follow-up associated persistent smoking with higher mortality and cessation with benefit.",
      "limit": "Repeated reports from this cohort are not independent replications; generalization beyond its population requires other cohorts.",
      "historical_anchor_only": false
    },
    {
      "year": "2004",
      "source_id": "P15329413",
      "design": "Never-smoker tumour sequencing",
      "finding": "EGFR-mutant adenocarcinoma was enriched among never smokers.",
      "limit": "Alternative causes are compatible with smoking causing a major share, not all tumours.",
      "historical_anchor_only": false
    },
    {
      "year": "2005",
      "source_id": "P15944214",
      "design": "Lifetime mouse inhalation study",
      "finding": "Long-term smoke exposure induced lung cancer with molecular changes.",
      "limit": "Species, dose and exposure conditions limit direct human quantitative extrapolation.",
      "historical_anchor_only": false
    },
    {
      "year": "2013",
      "source_id": "P23343063",
      "design": "United States smoking/cessation cohort",
      "finding": "Continued smoking reduced life expectancy; earlier cessation provided larger benefit.",
      "limit": "All-cause mortality estimates must not be relabelled as lung-cancer-specific effects.",
      "historical_anchor_only": false
    },
    {
      "year": "2016",
      "source_id": "P27811275",
      "design": "Human tumour mutational-signature analysis",
      "finding": "Smoking correlated with several mutational signatures across cancer types.",
      "limit": "Different signatures and exposures can overlap; a tumour signature alone does not prove universal exposure specificity.",
      "historical_anchor_only": false
    }
  ],
  "gaps": [
    {
      "id": "G1",
      "question": "Which molecular changes initiate cancer rather than accumulate later?",
      "source_ids": [
        "P8832894",
        "P27811275",
        "P15944214"
      ],
      "alternative": "Passenger mutation burden or promotion may accompany rather than define initiation.",
      "discriminating_test": "Exposure-resolved longitudinal airway sampling and lineage/driver analyses with matched controls; compare adduct, mutation and clonal expansion timing.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    },
    {
      "id": "G2",
      "question": "What determines persistent risk after cessation?",
      "source_ids": [
        "P10926586",
        "P15213107",
        "P23343063"
      ],
      "alternative": "Pre-existing clones, epigenetic injury and age-related processes may outlast exposure.",
      "discriminating_test": "Prospective cessation cohorts with repeated airway/genomic measurements, verified exposure and lung-cancer incidence; account for competing mortality.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    },
    {
      "id": "G3",
      "question": "How specific are tobacco-related signatures across co-exposures?",
      "source_ids": [
        "P27811275",
        "P8832894",
        "P15329413"
      ],
      "alternative": "Ambient carcinogens, second-hand smoke or shared repair processes may create overlapping patterns.",
      "discriminating_test": "Component-resolved exposure measures and independent tumour cohorts; quantify attribution uncertainty rather than assigning cause from a single signature.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    },
    {
      "id": "G4",
      "question": "Why do similarly exposed people develop different outcomes?",
      "source_ids": [
        "P15329413",
        "P15944214",
        "P27811275"
      ],
      "alternative": "Genotype, histology, airway biology and competing exposures may modify risk.",
      "discriminating_test": "Large prospective dose-resolved cohorts with predefined effect modifiers and mechanistic validation; separate susceptibility from necessity or sufficiency.",
      "gap_type": "bounded_causal_uncertainty",
      "interpretation": "An unresolved inference or scope limit in the checked evidence, not a claim that no relevant study exists anywhere."
    }
  ],
  "source_cards": [
    {
      "id": "P14772469",
      "pmid": "14772469",
      "doi": "10.1136/bmj.2.4682.739",
      "title": "Smoking and carcinoma of the lung; preliminary report.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/14772469/",
      "issue_year": "1950",
      "electronic_date": "",
      "access_depth": "metadata_only",
      "checked_details": "Identifier, title and publication metadata checked; original results not re-examined.",
      "publication_types": [
        "Journal Article"
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "abstract_metadata",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P15415260",
      "pmid": "15415260",
      "doi": "10.1001/jama.1950.02910390001001",
      "title": "Tobacco smoking as a possible etiologic factor in bronchiogenic carcinoma; a study of 684 proved cases.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/15415260/",
      "issue_year": "1950",
      "electronic_date": "",
      "access_depth": "metadata_only",
      "checked_details": "Identifier, title and publication metadata checked; original results not re-examined.",
      "publication_types": [
        "Journal Article"
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "abstract_metadata",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P8832894",
      "pmid": "8832894",
      "doi": "10.1126/science.274.5286.430",
      "title": "Preferential formation of benzo[a]pyrene adducts at lung cancer mutational hotspots in P53.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/8832894/",
      "issue_year": "1996",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, U.S. Gov't, P.H.S."
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P10926586",
      "pmid": "10926586",
      "doi": "10.1136/bmj.321.7257.323",
      "title": "Smoking, smoking cessation, and lung cancer in the UK since 1950: combination of national statistics with two case-control studies.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/10926586/",
      "issue_year": "2000",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, Non-U.S. Gov't"
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P15213107",
      "pmid": "15213107",
      "doi": "10.1136/bmj.38142.554479.AE",
      "title": "Mortality in relation to smoking: 50 years' observations on male British doctors.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/15213107/",
      "issue_year": "2004",
      "electronic_date": "2004-06-22",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, Non-U.S. Gov't"
      ],
      "correction_notices": [],
      "cohort_note": "British Doctors cohort; 20- and 50-year reports are not independent cohorts.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P15329413",
      "pmid": "15329413",
      "doi": "10.1073/pnas.0405220101",
      "title": "EGF receptor gene mutations are common in lung cancers from \"never smokers\" and are associated with sensitivity of tumors to gefitinib and erlotinib.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/15329413/",
      "issue_year": "2004",
      "electronic_date": "2004-08-25",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, Non-U.S. Gov't",
        "Research Support, U.S. Gov't, P.H.S."
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P15944214",
      "pmid": "15944214",
      "doi": "10.1093/carcin/bgi150",
      "title": "Life-span inhalation exposure to mainstream cigarette smoke induces lung cancer in B6C3F1 mice through genetic and epigenetic pathways.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/15944214/",
      "issue_year": "2005",
      "electronic_date": "2005-06-08",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Comparative Study",
        "Journal Article",
        "Research Support, N.I.H., Extramural",
        "Research Support, U.S. Gov't, Non-P.H.S.",
        "Research Support, U.S. Gov't, P.H.S."
      ],
      "correction_notices": [
        {
          "type": "ErratumIn",
          "pmid": "",
          "note": ""
        }
      ],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false,
      "notice_check_scope": "Linked notice presence was checked in the primary record; its scientific impact was not verified in this update."
    },
    {
      "id": "P23343063",
      "pmid": "23343063",
      "doi": "10.1056/NEJMsa1211128",
      "title": "21st-century hazards of smoking and benefits of cessation in the United States.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/23343063/",
      "issue_year": "2013",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, N.I.H., Extramural",
        "Research Support, Non-U.S. Gov't"
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "abstract_metadata",
      "complete_paper_examined_in_this_update": false
    },
    {
      "id": "P27811275",
      "pmid": "27811275",
      "doi": "10.1126/science.aag0299",
      "title": "Mutational signatures associated with tobacco smoking in human cancer.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/27811275/",
      "issue_year": "2016",
      "electronic_date": "",
      "access_depth": "abstract_excerpt_checked",
      "checked_details": "Primary record and selected abstract passages checked; no complete-paper appraisal credited.",
      "publication_types": [
        "Journal Article",
        "Research Support, Non-U.S. Gov't",
        "Research Support, U.S. Gov't, Non-P.H.S."
      ],
      "correction_notices": [],
      "cohort_note": "No independence claim made; cohort identity beyond the cited report was not exhaustively audited.",
      "baseline_access_depth": "full_text_complete",
      "complete_paper_examined_in_this_update": false
    }
  ],
  "access_counts": {
    "full_text_partial": 0,
    "abstract_excerpt_checked": 7,
    "metadata_only": 2
  },
  "browser_messages": 2,
  "targeted_check": {
    "pmid": "27811275",
    "provider_access": "selected primary full-text passages reported by Consensus",
    "independent_primary_body_crosscheck": false,
    "verification_scope": "Primary abstract/metadata checked. Additional Consensus full-text details remain provider-reported because a separately readable body was unavailable in this update."
  },
  "editorial_warning": "",
  "reading_limit": "This focused addendum does not establish 50–70 complete primary Methods/Results examinations per review. Baseline reading receipts and scores retain their original scope.",
  "method": "Case-specific Consensus records assisted gap discovery, chronology and targeted paper questions. Shared template wording about an amyloid-specific Deep follow-up is not evidence of a Deep run for this topic; the dated source records establish the actual use and access limits. Primary identifiers, selected abstract passages, correction notices and available primary-body passages were cross-checked. Generated absence cells, duplicate milestones and unsupported access claims were rejected."
}